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Babies are born dirty, with a gutful of bacteria

By Jessica Hamzelou

IT HAS long been assumed that the fetus lives in a sterile world, protected from the countless bacteria that fill its mother’s gut and cover the surface of her body. A baby’s first gut flora was thought to be collected at birth – either from the mother’s vagina or from the environment it is born into. But it’s time for a drastic rethink&colon; it appears that we are in fact born dirty – bacteria colonise our guts in the womb, where they begin to shape our immune systems and influence our risk of disease. What’s more, this …